True to size and fit. The UA Tech 2.0 as been out for a couple years now. I own several of these - needed an extra one in a different color. I wear them for physical activities (hiking/running/gym) but also as undershirt. I've tried many other brands, they are the only one comfortable yet durable I was able to find.

I bought this specifically to wear whilst doing a 130km hike (cape 2 cape in WAs SW) for charity. No chaffing whatsoever and we raised over $17k for mental health and suicide prevention!!! it was a 5-7 day hike which we finished in under three... wore this day one and nothing but comfortable all day!

I wore this shirt under a light windbreaker for a half marathon, during which it rained about a third of the time (including some heavy downpours towards the beginning). The shirt remained comfortable throughout the run, and didn't cause any chafing or discomfort despite the prolonged damp conditions. Towards the end of the race and after the race, it dried quickly, too, as the rain let up. Yet another Under Armour running product that I'm completely satisfied with!